Production or treatment of pigments and textile and other materials containing them



titanium dioxide.

Patented Apr. 7, 1942 UNIT-ED STATES PATENT OFFICE 2,278,540 PRODUCTION on TREATMENT or PIG- DI'ENTS AND TEXTILE AND OTHER MA! TERIALS CONTAINING THEM George Holland Ellis and Edmund Stanley, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Application July 23, 1938, Serial No. 221,010. In Great Britain September 1, 193': Y

' Claims.

Artificial silk having a low lustre is extensively manufactured with the aid of titanium dioxide. A small proportion of this material may be incorporated in the spinning solution from which the artificial silk is formed or titanium dioxide or hydrated titanium dioxide may be incorporated in the already spun artificial silk, e. g. by interaction of suitable reagents on the material, or by treating the material with an aqueous dispersion of titanium dioxide. It has been found, however, that when artificial silks containing titanium dioxide are coloured the colourations are in general not so fast to light as those yielded by the same dyestuffs upon similar materials free from titanium dioxide. This lack of fastness to light is particularlynoticeable while the material is wet. Further, artificial silk containing titanium dioxide frequently loses strength much more rapidly when exposed to light than similar artificial silk free from According to U. S. Patent No. 2,206,278, these undesirable effects of titanium dioxide are minimised by associating or treating it with a compound of copper.

We have now found that compounds of metals of group V, subgroup A, of the periodic table, especiallyvanadium compounds, are very valuable, in place of or in addition to the, aforementioned copper compounds, for minimising the aforesaid bad effects of titanium dioxide. The valuable efiects of vanadium compounds may be secured by treating the titanium dioxide with a vanadium compound before the titanium dioxide is incorporated in the artificial silk or other material, or by treating the artificial silk or other material containing the titanium dioxide with the vanadium compound either before, during, or after any colouring of the material.

I If desired the treatment of a textile or other product with the vanadium compound may precede or be carried out simultaneously with the incorporation of titanium dioxide in the material was a step in a process of effecting such incor- ;'poration. Moreover, a cellulose ester or other substance may be treated with the vanadium compound prior tov conversion into filaments, e. g. while in the form of a spinning or film-forming solution, and before or after incorporation of titanium dioxide therewith.

Conveniently a water-soluble compound of vanadium is employed, for instances salt of the metal with an acid, or a compound in which the metal forms part of an anion, for example a vanadate. Examples of suitable compounds are vanadium trichloride and ammonium vanadate. The treatment or association of the titanium m dioxide with the vanadium compound is applitanium dioxide and having a basis of cellulose acetate or other cellulose ester or ether.

The titanium dioxideor material containing it may with advantage be treated with an aqueous solution containing a vanadium compound. For example, titanium dioxidesufilciently finely sub-' divided to render it suitable for incorporation in an artificial silk spinning solution may be heated or boiled with a 0.1 to 5%, e. g. 0.3 to 0.5%, aqueous solution-of ammonium vanadate. Again, atextile material, for example an artificial silk,

containing titanium dioxide may be heated with a dilute aqueous solution, e. g. a 0.05 to 1% solution, of ammonium vanadate. If desired the solution of the vanadium compound may' contain an acid, for example formic acid, acetic acid,v or other organic acid. The amount of acid used maybe about half the weight of the vanadium compound.

When treating textile materials, foils, or the like containing titanium dioxide, the treatment liquid may contain a swelling agent for the cellulose acetate or other material forming the basis of the textile, foil onthe like, in order to facilitate penetration of the material by the treatment liquid.

After treatment with the aqueous solution the titanium dioxide or material containing it may be washed; The material may then bedrled, or'

further processed without drying, as may be convenient. For example, in the case of a textile material containing titanium dioxide, the wet material may be dyed without intermediate drycable in the case of natural textile fibres containing titanium dioxide, for example natural films, foils, plastics and the like containing tirial may be subjected to a treatment to ensure the fixation of an oxide, hydroxide, or other water-insoluble compound of vanadium in the material. For example suitable reagents may be allowed to interact in the presence of the titanium dioxide so as to form an insoluble vanadate on the titanium dioxide.

Other methods of associating the vanadium compound with the titanium dioxide may, however, be employed. ,For example the titanium dioxide may merely be intimately mixed with the vanadium compound.

The vanadium compound may be employed in quite small proportion, for example a proportion of the order of .05 to 5%, especially .5 to 2%, based on the weight of the titanium dioxide.

The new process enables improved results as regards fastness to light to be obtained when materials containing titanium dioxide are coloured with dyestuffs of widely varying type. For example the improvement is particularly good in the case of water-soluble azo dyestuffs having a substantive affinity for regenerated cellulose. Again, the dyestuffs may be azo dyes, soluble or insoluble in water, having a direct affinity for cellulose acetate. When a copper compound is also used, this is preferably present in amount insuflicient to impart any substantial colouration to the titanium dioxide. Other classes of dyes the colourations of which on textile materials containing titanium dioxide may be improved by the new process are the amino-anthraquinone dyestufis having direct ailinity for cellulose acetate, especially those dyestuii's yielding violet, blue or green shades on this material. The improvement is particularly good in the case of dyeings made with 1.4-diamino-anthraquinone or 1.4-amino-oxy-anthraquinone and their substitution products, for example 1.4-di-(alkylamino)-anthraquinones. An improvement may be obtained even in the case of those dyestuifs normally regarded as having a very high degree of fastness, for example vat dyestuffs, e. g. those of the indigoid series, and the water-insoluble azo dyestuifs produced on the fibre, for example those produced by coupling diazotised amines with B-naphthol, arylamides of 2:3-oxy-naphthoic acid, or diacyl-acetyl derivatives of aromatic diamines.

Although the invention has been described with special reference to the use of vanadium compounds, it includes the use of other metals of group V, subgroup A, of the periodic table, for example tantalum.

The following examples illustrate the invention but are not to be regarded as limiting it in any way:

Example 1 Finely divided titanium dioxide is heated for 30 minutes at 85 to 90 C. with 20 times its weight of an aqueous solution containing 4 grams per litre of ammonium vanadate and 1.5 grams solution thereafter spun into filaments by dry spinning methods. Shades yielded on this artificial silk with, for example, 1.4-di-(methylamino) -anthraquinone are of much better fastness to light than those on similarv artificial silk made with untreated titanium dioxide.

Example 2 A fabric of cellulose acetate yarns having a low lustre due to the presence of titanium dioxide therein is treated for one hour at C. with an aqueous solution containing .5% of ammonium vanadate and .2% of formic acid. The material is well washed and is then dyed with 1.4-di- (methylamino)-anthraquinone. In this way a blue shade is obtained which is much faster to light than that obtained when the treatment with ammonium vanadate is omitted.

It is to be understood that the present invention is not concerned with processes in which titanium dioxide is mixed with a compound of vanadium or other metal, the mixture being calcined at a high temperature, e. g. 500l000 C., to produce a tinted pigment, and that such treatments of titanium dioxide and titanium dioxide pigments obtained by such treatments are not included within the scope of the appended claims.

Having described our invention, what we desire to secure by Letters Patent is:

1. Textile and other materials which are delustered with titanium dioxide and have improved properties as regards their tendency to lose tenacity, and, if dyed, to fade on exposure to light, wherein the titanium dioxide is associated with a vanadium compound by treating it with an aqueous medium containing the vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

2. Textile materials containing cellulose acetate filaments which are dyed with an azo dyestufl having a direct afllnity for the cellulose acetate, which are delustered with titanium dioxide and which have improved properties as regards their tendency to lose tenacity and to fade on exposure to light, wherein the titanium dioxide is associated with a vanadium compound; by treatingit with an aqueous medium containing the vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.-

3. Textile materials containing cellulose acetate filaments which are dyed with an aminoanthraquinone dyestuif having a direct aflinity for the cellulose acetate, which are delustered with titanium dioxide and which have improved properties as regards their tendency to lose tenacity and to fade on exposure to light, wherein the titanium dioxide is associated with a vanadium compound by treating it with an aqueous medium containing the vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

4. Process for the production of a titanium dioxide delustering agent having improved properties as regards its efiect on the tenacity of textile and other materials containing the same, and on the light-fastness of such materials when dyed, which comprises associating titanium dioxide with a compound of vanadium by treating it with a dilute aqueous solution of a vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

5. Process for the production of a titanium dioxide delustering agent having improved properties as regards its efiect on the tenacity of textile and other materials containing the same, and on the light-fastness of such materials when dyed. which comprises associating titanium dioxide with a compound of vanadium by treating it with a dilute aqueous solution of a Mind vanadium compound containing a lower fatty acid at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

6. Process for the production of a titanium dioxide delustering agent having improved properties as regards its efiect on the tenacity of textile and other materials containing the same,

and on the light-fastness of such materials when dyed, which comprises precipitating on the titanium dioxide at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure from a dilute aqueous solution or a soluble compound of vanadium ODS-5% (based on the weight of the titanium dioxide) of an insoluble compound of vanadium.

7. Process for the production of a textile or other material delustered with a titanium dioxide delustering agent and having improved properties as regards its tendency to lose tenacity and, if dyed, to fade on exposure to light, which comprises treating a textile or other material containing titanium dioxide as a delustering agent with an aqueous medium containing a vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

8. Process for the production of a dyed textile material delustered with a titanium dioxide delustering agent and having improved properties as regards its tendency to lose tenacity and fade on exposure to light, which comprises treating a dyed textile material containing titanium dioxide as a delustering agent with an aqueous solution of a vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

9. Process for the production of a dyed textile material delustered with a titanium dioxide delustering agent and having improved properties as regards its tendency to lose tenacity and fade on exposure to light, which comprises treating a textile material containing cellulose acetate filaments, which are dyed with an azo dyestufi having a direct aflinity for the cellulose acetate and which are delustered with titanium dioxide, with an aqueous solution of a vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure.

10. Process for the production of a dyed textile material delustered with a titanium dioxide delustering agent and having improved properties as regards its tendency to lose tenacity and fade on exposure to light, which comprises treating a textile material containing cellulose acetate filaments, which are dyed with an aminoanthraquinone dyestufi and which are delustered with titanium dioxide, with an aqueous solution 0! a vanadium compound at a temperature not exceeding the boiling point of the aqueous medium at atmospheric pressure. GEORGE HOLLAND ELLIS. EDMUND STANLEY. 

